1. Field of the Invention
This invention relates generally to heating apparatus, and more particularly to a method and apparatus utilizing submerged products of combustion for heating liquids.
2. Brief Description of the Prior Art
Heinze, U.S. Pat. No. 2,890,166 discloses a process and apparatus utilizing submerged combustion in which a first body of liquid is in direct contact with a submerged flame. A second body of liquid communicates with the first by a passageway positioned above the flame whereby the first body of liquid can overflow into the second body of liquid. Incondensible gases are removed from a space above the second body of liquid. A third body of liquid communicates with the second and condensible vapors are removed from a space above said third body of liquid, and a portion of the resultant liquid from the third body of liquid is returned to the first body of liquid at a point below the submerged flame.
Wyatt, U.S. Pat. Nos. 4,418,651 and 4,441,460 discloses methods and apparatus for heating and utilizing fluids by the use of vapor generators. A flowing fuel/air mixture is burned in the presence of a stream of feed water to produce a stream of steam and non-condensibles at low pressure which is then heat exchanged with a stream of the fluid to be heated and utilized. The heated fluid may be divided into two or more streams during the heat exchange, with different amounts of heat delivered into each stream. The heat exchange is so conducted as to condense the steam from the stream of steam and non-condensibles, and the condensate so formed is selectively recycled to the vapor generator as feed water.
DeBord, U.S. Pat. No. 3,756,171 discloses an air pollution control system used in the burning of rubbish wherein the noncombustibles from the incinerator are caught and cooled by being forced into a water bath where it is scrubbed with water, filtered, and deposited in a final bath tank to then be purified and deposited into the municiple drain system.
Mercer, U.S. Pat. No. 3,572,264 discloses another system for removing visible smoke and suspended particles by washing and filtering the products of burning including a method of recirculating the burned gases from the cleaning process into the combustion chamber.
Iwanaga et al, U.S. Pat. No. 3,224,170 discloses a gas purification apparatus wherein the gas to be purified is passed through a tube submerged in a tank of purification liquid along with a portion of the purification liquid. The semi-purified gases exit the end of the tube and carry some of the liquid with it into a funnel tube. Consequently, the gas and liquid rise in a coexistent state to a level higher than the liquid level in the tank. Finally, the gas separates from the liquid and flows out from the funnel tube in a purified state.
The present invention is distinguished over the prior art in general, and these patents in particular by apparatus for heating a liquid by circulating combustion products. The apparatus comprises a housing having a liquid-containing reservoir compartment and a burner compartment thereabove with a fuel burner therein for burning a mixture of air and combustible gases, liquids or particulate solids. An electric motor mounted above the burner has a shaft extending downward into the liquid in the reservoir with an impeller mounted on the lower end submerged in the liquid. Rotation of the impeller produces suction in the liquid dwawing in hot combustion gases and dispersing the same as hot gas bubbles which heat the liquid more efficiently. A portion of the liquid is conducted from the reservoir and discharged close to the burner to cool the burning mixture. A coil submerged in the reservoir allows a second liquid to be heated by the liquid in the reservoir. Both liquids may recycled for various residential or industrial uses.